Electrical stimulation for medical therapy and physical rehabilitation is a very old and well established technique. Basically, it relies upon electrical impulses applied through two separate electrodes. The technique was first described as early as 1801 for use in certain paralytic conditions, palsys and neurotic conditions.
The application of amperage in varying quantities can produce considerable differences in the muscular action generated by the electrical current. Since the skin has a resistance, the currents generated by the electrodes act as a considerable irritant on the skin. It is well-established that it is necessary to use a covering on the electrode particularly if the galvanic action is intended for the deeper tissues. Now it is accepted practice, that unless a definite type of action is desired from a bare metal electrode, such as an electrolysis or metallic ionization, a galvanic current should be applied only with covered electrodes. This avoids the very painful irritation and burns which will surely result if even a moderately intense current is employed with bare electrodes.
For medical uses of electric currents for various therapeutic applications, bare metal electrodes cannot be used on the surface of the body. Thus, it has been always observed that when such electrodes have been used there results an inevitable electrolytic decomposition which occurs under the metal. Moreover, there is a considerable burn risk which is caused by acid, caustic or electrical action.
If it is essential that low-tension currents be used, then the metal elctrodes are conventionally covered with gauze or other absorbent material in sufficient width to overlap the edges of the metal. These pads are used for galvanic faradic-sinusoidal treatments. The pad on these electrodes is usually soaked with a saline solution which serves to soften the skin and ease the current.
It also diffuses the electrolytic decomposition products and tends to prevent chemical burns.
The burns caused by improper contact with too thinly coated metal electrodes or bare metal electrodes can be quite severe resulting in blisters which in turn lead to secondary infection which are very painful and heal slowly.
One of the more important areas which is amenable to treatment by the critical use of electrical stimulation is that involving denervated muscle. The stimulation retards the progression of atrophy. Furthermore, it may be necessary to have several stimulation sessions a day to retard the atrophy.
This desirably would be facilitated if the electrodes stay in contact with the afflicted area for a long period of time without constant removal or reimplacement. Even those electrode contact media which are presently commercially available do not permit the use of bare electrodes. They must be used in combination with the gauze covering of the electrode. Furthermore, the gels which are commercially available suffer the sever disadvantage that they very quickly liquefy under the influence of the ingredients in human perspiration.
An area in which the burned skin problem is particularly acute in utilizing the technology of the prior art is that of electro-shock thereapy and the defibrillation of hearts.